Originally Posted by Hawk
Well, she carries Drogon in on her shoulder, so he was still small. He burns it down by breathing fire on the floating heart and trying to eat it. Then the fire spreads quickly as everything in there, including the undying themselves, is old, brittle, and ready to go up in flames.
Yeah. We might not have really seen what even a tiny dragon can do at this point, as well. They may be saving that for that particular scene. He's all dainty and such with his flame when eh's eating the meat she offers. Maybe he can go beast mode with the flame when he wants, even as a small dragon.